Haha! very good :) On Friday, December 18, 2015 at 10:39:49 AM UTC+13, Eric Krause wrote: > > I just did that this morning. > > On Thursday, December 17, 2015, spike22 <[email protected] > <javascript:>> wrote: > >> Hi Eric, that's really interesting! I'll give it a whirl and report back >> :) I might do a documentation pull request to clarify this too. >> >> Have a great day! >> >> Brendon >> >> On Friday, December 18, 2015 at 6:23:50 AM UTC+13, Eric Krause wrote: >>> >>> I responded on stackoverflow, but I'll do here as well so that it is >>> covered everywhere on the internet. >>> >>> In my case I was doing something similar to what you were doing and was >>> running into the same issue with the join table being deleted instead of >>> destroyed. >>> >>> I started looking through the code and I believe the documentation is >>> just out of date. >>> [has_many_through_association]( >>> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131 >>> ) >>> >>> All you need to do is add the dependent: :destroy to the has_many >>> :through relationship. >>> >>> class User >>> has_many :partnerships, dependent: :destroy >>> has_many :partners, through: :partnerships, dependent: :destroy >>> end >>> >>> The pain I was dealing with was: >>> >>> user.partner_ids = [1,2,3] >>> #creates the relationships >>> user.partner_ids = [] >>> #was deleting the records from partnerships without callbacks. >>> >>> The dependent: :destroy on the partners relationship fixed that. >>> Callbacks are now being run and things are good again. >>> >>> Eric >>> >>> On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote: >>>> >>>> I've asked this on on Stack Overflow but didn't receive much of a >>>> response: >>>> >>>> The Rails 4 documentation says this regarding destroy callbacks on the >>>> join model for a has_many :through relationship: >>>> >>>> collection=objects Replaces the collections content by deleting and >>>> adding objects as appropriate. If the :through option is true callbacks in >>>> the join models are triggered except destroy callbacks, since deletion is >>>> direct. >>>> >>>> Thankfully it's documented at least, but I want to know why on earth >>>> this is the case? It makes more sense to trigger destroy callbacks (or >>>> have >>>> the option to) on a :through since these types of models can have destroy >>>> callbacks and other associations. >>>> >>>> In my case I had a has_and_belongs_to_many relationship on the join >>>> tables model off to another model. The records on that second join table >>>> would never be deleted when the associated records on the first join table >>>> were deleted. I resorted to this which feels hacky, and I have to repeat >>>> myself on each side of the :through relationship: >>>> >>>> class SchoolsTemplate < ActiveRecord::Base >>>> >>>> belongs_to :school >>>> belongs_to :template >>>> >>>> has_and_belongs_to_many :groups >>>> >>>> end >>>> >>>> >>>> class School < ActiveRecord::Base >>>> >>>> has_many :schools_templates, dependent: :destroy >>>> has_many :templates, through: :schools_templates, before_remove: >>>> :remove_groups_school_templates >>>> >>>> private >>>> def remove_groups_school_templates(template) >>>> schools_templates.where(template: template).first.groups.clear end >>>> >>>> end >>>> >>>> There's a validation to 'ensure' uniqueness on the join tables records >>>> between the two foreign keys, so that's why I can call first in the >>>> callback. >>>> >>> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "Ruby on Rails: Talk" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/rubyonrails-talk/eGJRC4hDDuQ/unsubscribe >> . >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/rubyonrails-talk/9eb239ab-b444-4b74-837d-503b589516a2%40googlegroups.com >> >> <https://groups.google.com/d/msgid/rubyonrails-talk/9eb239ab-b444-4b74-837d-503b589516a2%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > > -- > > Eric Krause >
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